Title :
Terahertz emission from indium oxide films on MgO substrates excited at a photon energy below the bandgap
Author :
Estacio, Elmer ; Que, Christopher T. ; Awitan, Fritz C B ; Bugante, John I. ; De Vera, Chesca ; Azares, Jonathan ; De Vero, Jeffrey ; Somintac, Armando S. ; Sarmago, Roland V. ; Salvador, Arnel A. ; Yamamoto, Kohji ; Tani, Masahiko
Author_Institution :
Res. Center for Dev. of Far-Infrared Region, Univ. of Fukui, Fukui, Japan
fDate :
Aug. 28 2011-Sept. 1 2011
Abstract :
Indium oxide (In2O3) films grown on MgO substrates by thermal oxidation were excited by femtosecond laser pulses having photon energy lower than the bandgap. The emission of terahertz (THz) pulse was observed using time domain spectroscopy in the reflection-geometry excitation. Results show that THz generation saturates at an excitation fluence of ~400 nJ/cm2. Although two-photon absorption has been ruled out, the actual THz emission mechanism and still has to be verified and is temporarily attributed to carriers from defect level absorption possibly being driven by a strain field due to the lattice mismatch between the In2O3 and the MgO substrate.
Keywords :
indium compounds; laser beam effects; magnesium compounds; optical lattices; optical pulse generation; semiconductor thin films; In2O3; MgO; bandgap; femtosecond laser pulses; indium oxide films; lattice mismatch; photon energy; terahertz emission; thermal oxidation; time domain spectroscopy; Indium; Optical films; Oxidation; Photonic band gap; Substrates; Ultrafast optics;
Conference_Titel :
Quantum Electronics Conference & Lasers and Electro-Optics (CLEO/IQEC/PACIFIC RIM), 2011
Conference_Location :
Sydney, NSW
Print_ISBN :
978-1-4577-1939-4
DOI :
10.1109/IQEC-CLEO.2011.6193807
